Four Hundred Fifty-One Degrees is not a boy band. The group was founded by a boy, and it is led by a boy, but its ranks are primarily girls. It came together just 18 months ago and, depending on the week, it claims 15 to 20 members. That fluctuation should not be misread as a lack of commitment: The members have matching T-shirts, with “451 Degrees” emblazoned across the fronts. That said, matching T-shirts should not be misread as popularity: Until the other day, 451 Degrees was not especially well-known.

This is, after all, a book club — a small book club at Lane Tech College Prep High School, which has 4,200 students and more than 60 official clubs, including a Dr. Who Club, a Lithuanian Club and a Ping Pong Club.

Then, about a week and a half ago, word swept through Lane that a Chicago Public Schools directive ordered all copies of the Marjane Satrapi graphic novel “Persepolis” removed from classrooms and libraries.

Its name, of course, is a clever nod to the temperature at which books burn in “Fahrenheit 451,” Ray Bradbury's dystopian classic about a repressive, book-confiscating future America. In fact — well, what do ya know? — about the same time “Persepolis,” which tells the autobiographical story of a young girl navigating her way through a repressive, revolutionary Iran, was being yanked, 451 Degrees was having its regular Wednesday afternoon meeting in room 231, talking about the themes in “Fahrenheit 451.”

Irony wasn't among them.

Not until later.

Said Todd, 451 Degrees' president: “It cracks me up to think, just as the email about pulling the book was going around the school, we were wrapping our conversation about ‘Fahrenheit 451' — which we're named after but hadn't read yet — having the greatest discussion ever, about freedom of speech, its limitations …”

Said Evie Lacroix, the group secretary: “It was super-eerie in retrospect, because here we were talking about manipulation and repression, and here the CPS were, trying right then to manipulate and repress us!”

Said Grace Barry, the vice president: “We were a chilled-out club. We ate snacks, we talked. We planned to read Margaret Atwood next, now we had to go for immediacy and start ‘Persepolis.'” She added: “I don't want to end up on some list or something, but I think I might want to read ‘The Anarchist Cookbook' next.”

Remember, CPS: No one is born a revolutionary.

To be fair, the school district, which began pulling copies of “Persepolis” because of a complaint about a single page that contained brief and harrowing (though hardly gratuitous) images of torture in Iran, later backpedaled and said the directive was misunderstood, badly worded and intended only for seventh-grade classrooms.

“But you have to wonder why a student in Chicago, not exactly a backwater, would feel the need to start a group like this a year earlier,” said Barbara Jones, director of the Office for Intellectual Freedom of the Chicago-based American Library Association. She had never heard of a banned-books club in a high school, but wondered if someone in 451 Degrees had ever had a book taken away — “which, frankly, is how I ended up doing this; I remembered how chilling it was to be told by a librarian that I couldn't read Karl Marx. Which I finally read and was incredibly bored by, but it's the principle of the thing.”

Indeed, 451 Degrees began mildly.

Todd told me his first experience with a controversial book was “The Hunger Games.” He read it as a freshman, and though it was not banned in Chicago, it had been controversial elsewhere. Todd reads a lot; he said he plans on being a book editor.

“But I never found a club I was into at Lane,” he said, “and if I was going to do a club, I was going to have fun, not just throw something on a resume.” He also didn't want a general-interest book club, but after he saw a sign for Banned Books Week (which is in September), he thought there would be a specificity and purpose to a club devoted only to books challenged in libraries and schools.

He landed a faculty adviser, began making posters (an image of a book silhouetted by a flame) and started recruiting friends: “When Levi said we would read only banned books, that sounded extra awesome,” said Tori Lieggi, the group treasurer. “Have you ever heard of someone in a school seeking out banned books?”

Talking to members of 451 Degrees, it's hard not to be reminded that a banned book becomes a forbidden fruit. On the other hand, do not assume that a book club like this is a fleeting teenage act of provocation.

Last week I met with Todd after school. We sat in a cafe in Lincoln Square, not far from his North Center high school. He brought along senior Alexa Repp, 17, a friend who also happened to be one of the leaders of the student protests that sprang up after “Persepolis” was pulled. She had long red hair and was stylishly bundled in a scarf. Todd was lanky, poised, with a small curl of hair that made me think of Tin Tin. They were also alarmingly self-possessed, ridiculously well-spoken for teenagers and fond of air quotes. (“To be honest with you, I frequently ask myself where my son comes from,” Todd's father, Stuart Iseminger, told me later.)

Repp said, “I love banned books and have made an effort to read banned books for a while now, because, for some reason, there is something genuine in a lot of banned books, which is what probably scares adults.”

“Yeah, but you're not in 451 Degrees,” Todd said.

“Yeah I know, weird,” she said. (Indeed, when I asked senior Katie McDermott, Repp's friend and fellow Lane protester, if she was a member of the Levi Todd banned-books club, she said, “What's a Levi Todd?”)

Todd told me that when the group started, the members researched where books were banned and what books were banned. “One that kept coming up was, oh, I forget, from a Russian writer, man falls in love with a child …”

“‘Lolita,'” I said.

“‘Lolita,'” he said. “We didn't start with that. We thought we'd spend the first year playing it safe, so the first book was Sherman Alexie's ‘The Absolutely True Diary of a Part-Time Indian,' which has some random controversial elements but also had an instant talking point because the Lane Tech mascot is a Native American, which you are either for or against, but it's something. Also, there's poverty, American culture. … The next book was less banned than controversial (‘Skinned' by Robin Wasserman), and the concept was basically, it's the future, your brain can be scanned and inserted into a robot — you would like it, actually,” he told Repp.

“I'm writing a paper on trans-humanism, actually,” Repp said.

“Animal Farm” didn't go as well, Todd said, because “everybody kind of knows communism doesn't work by now, so there's not a lot to discuss anymore. But ‘Fight Club,' the book, there was a lot to talk about.”

I asked why.

“Because — ”

“Because,” Repp interrupted, “the first rule of Fight Club is to not talk about Fight Club.”

Todd sighed. “Yes,” he said. “But no — the writing style is just so different, and the character is having this mental downward spiral, and he talks about how it feels better when he can destroy something beautiful.”

“I think that's a recurring thing in banned books,” Repp said. “The whole destroying something beautiful. I'm rereading ‘The Fountainhead' and this daughter, she buys a sculpture in Italy and throws it down the stairs.”

But deeper themes rarely lead to banned books, I said, it's usually a single objectionable passage or image.

“It's one page of ‘Persepolis'!” Todd said.

“Because people who object to this stuff don't read entire books,” Repp said. Still, the group has received nothing but support from Lane Tech, Todd said, “no push-back.” (Their adviser, English teacher Brian Telles, told me response from the school and himself has been “only enthusiastic.”)

In fact, Todd expects membership to spike slightly because of the “Persepolis” controversy, though he is a realist: He understands that the life span of a controversy is a blink, and that 451 Degrees is no easy sell.

He told me a story: “When we were talking about ‘Fahrenheit 451,' the same day they were pulling the book, we did this exercise. I asked everyone to pretend we're the world, it's a utopia/dystopia, let's figure out if we can create a society where everyone is happy. Everyone had to finish the sentence: ‘In my ideal world there is …' We went in a circle. If anyone was opposed to anyone's ideal world, they could raise their hand, that idea would not be adopted. And you couldn't argue. Anyone is opposed — that's it, not included. But, of course, everyone started arguing — because you can't create an ideal world and you can't make everyone happy all the time.”